Democratic Sen. Joe Bolkcom, of Iowa City, says he needs both Republicans and Democrats from the state House and Senate to support the bill.

So far, he says the GOP members have shown little interest in publicly endorsing the legislation.

Under the measure, patients with certain medical conditions could obtain medical marijuana if they got a prescription from a physician and receive authorization from the state.

Parents of children with epilepsy spoke in favor of the bill at a news conference Tuesday, saying that in other states children with similar conditions had found relief taking marijuana in an oil form.